[FFmpeg-user] Concatenating two MPEG4 AAC movies fails with "invalid, clipping"

[Nikolas Borrel-Jensen]

Thanks for your reply.

Obviously the intro movie is not AAC, but the other movie is.

My version of ffmpeg is 1.2, I will update and follow your instructions! I will probably need to build it from source, since the AAC encoder is not part of the binaries (as far as I know, AAC is a proprietary format).

Nikolas

> Den 21/05/2015 kl. 18.03 skrev Moritz Barsnick <barsnick at gmx.net>:
> 
> On Thu, May 21, 2015 at 17:14:13 +0200, Nikolas Borrel-Jensen wrote:
>> I’m concatenating two AAC encoded movies in a mp4 container as
> 
> AAC? Are you sure? One doesn't even have an audio track. I'm not sure
> how the concat demuxer handles that. But anyway:
> 
>> ffmpeg -f concat -i /concat_scripts -c:a copy -c:v copy output.mp4
>> 
>> but I get a bunch of error messages like
>> 
>> [mp4 @ 0x7fbc61821400] st:0 PTS: 5433 DTS: 5412 < 35774 invalid, clipping
>> [concat @ 0x7fbc61801200] Invalid stream index 1
>> [mp4 @ 0x7fbc61821400] st:0 PTS: 5453 DTS: 5432 < 35775 invalid, clipping
> 
> You are requested to post the complete command line and the full, uncut
> console output. And that for many very good reasons. One of them: I
> suspect you are using a wrong or old version of ffmpeg.
> 
> That's why the other common request is for you to use as new a version
> of ffmpeg as possible. Recent binary builds from git are available for
> many platforms, if you can't build yourself.
> 
> With my recent ffmpeg, I get:
> [...]
> Press [q] to stop, [?] for help
> [concat @ 0x9e15d60] New audio stream 0:1 at pos:44 and DTS:3.10168s
> [mp4 @ 0x9e1fb40] Non-monotonous DTS in output stream 0:0; previous: 35600, current: 1822; changing to 35601. This may result in incorrect timestamps in the output file.
> [mp4 @ 0x9e1fb40] Non-monotonous DTS in output stream 0:0; previous: 35601, current: 1842; changing to 35602. This may result in incorrect timestamps in the output file.
> [mp4 @ 0x9e1fb40] Non-monotonous DTS in output stream 0:0; previous: 35602, current: 1862; changing to 35603. This may result in incorrect timestamps in the output file.
> 
> The resulting file does _not_ play well for me, but: That's probably a
> different issue. I don't have the solution for that and leave that
> question open.
> 
> Incidentally, what works for me is the MPEG-TS method described here:
> https://trac.ffmpeg.org/wiki/Concatenate#protocol
> But the audio from the second file incorrectly starts at the beginning
> of the resulting video, it seems the concat protocol doesn't handle
> that as expected. Your intro video would need some blank audio to fill
> the gap (either inserted when you generate the intro, or generated by
> ffmpeg during your conversion to match the second video).
> 
> Moritz
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